A % button that shows the progress through the entire book as a percentage and opens the quick navigation bar when clicked

In most EPUB books, there are multiple chapters. While there is already a progress bar that shows progress within a single chapter, how about adding a practical and functional “% button” next to it that shows the progress of the entire book as a percentage, and when tapped, opens a quick scroll bar at the bottom that allows easy forward and backward navigation throughout the entire book? =>: The green progress bar you recently added is really well designed. However, it only shows the progress within the current chapter, not the progress of the entire book. Would it be possible to add a button like the one I marked in red in the image? This button would always be visible on the screen and would display the overall progress of the book as a percentage. When tapped, it could open a progress slider that allows the user to move forward or backward within all the book, like Moon+ Reader. This way, users would be able to see their overall progress through the entire book directly on the main screen, and quickly navigate forwards and backwards with ease.